The present disclosure relates generally to extruded sheet structures and, more particularly, to an extruded transparent/translucent sheet suitable for roof structures.
Corrugated sheets of several types of materials are used for roof cladding structures. While many of these types of corrugated sheet materials are not light transmitting, it is sometimes desirable to receive natural daylight inside in commercial and residential buildings. Thus, at certain locations along a roof structure, the corrugated roof sheets or panels (e.g., metal sheets, glass fiber reinforced polyester, PVC) are replaced with transparent or translucent sheets. Typically, such transparent/translucent sheets are formed by extrusion of various types of thermoplastic resins such as polycarbonates. In fact, these extruded thermoplastic sheets are being used in an increasing range of commercial and residential applications, in view of the balance of light transmission, thermal insulation and strength properties of the sheets.
A further consideration in implementing thermoplastic sheets as a transparent/translucent roof material is the integration thereof with conventional, non-transparent roof panels. When used in a horizontal or slightly sloping installation, such as a skylight, or even in a vertical or steeply sloped installation, the sheets may be subjected to loads of snow and ice, or to wind and suction forces in several directions. Furthermore, there is also the issue of providing for relatively easy installation of the thermoplastic sheets between the non-transparent roof sheets. In order to maintain a consistent and attractive look, it is often preferable to provide the transparent sheet with the same or similar profile(s) as the non-transparent corrugated sheet.
Generally, however, existing thermoplastic sheet designs have not lent themselves to easy integration with conventional roof cladding panels while also maintaining certain strength and impact requirements. On one hand, those panel structures that incorporate features for both integration capability and strength are generally characterized by more complicated designs that often include additional mounting components such as springs or other supports. Such complicated designs are not easily and inexpensively made by an extrusion process. On the other hand, those panel designs that can be extruded do not provide the desired stiffness and impact strength.